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Identification Studies (identification + studies)
Selected AbstractsLevonorgestrel-releasing (20 ,g/day) intrauterine systems (Mirena) compared with other methods of reversible contraceptivesBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 10 2000R. S. French Research Fellow Objective To assess the relative contraceptive effectiveness, tolerability and acceptability of the levonorgestrel-releasing (20 ,g per day) intrauterine system (LNG-20) compared with reversible contraceptive methods in women of reproductive age. Design A systematic review and meta-analysis of randomised controlled trials. Identification Studies were identified through seven databases, and by contacting investigators and organisations working in the contraceptive field. Main outcome measures Unplanned pregnancy and continuation of contraceptive method. Results Five of the seven randomised controlled trials which met the inclusion criteria were included in the meta-analyses; four were comparisons of the LNG-20 intrauterine system with nonhormonal intrauterine devices. LNG-20 intrauterine systems were compared with intrauterine devices divided into two categories, those > 250 mm3 (Copper T 380 Ag and Copper T 380 A intrauterine devices) and those , 250 mm3 (Nova-T, Copper T 220C and Copper 200 intrauterine devices). Pregnancy rates for the LNG-20 intrauterine system users were significantly less likely to become pregnant compared with users of intrauterine devices , 250 mm3, and significantly less likely to have an ectopic pregnancy. LNG-20 intrauterine system users were more likely to experience amenorrhoea and device expulsion than women using intrauterine devices > 250 mm3. LNG-20 intrauterine system users were significantly more likely than all the intrauterine device users to discontinue because of hormonal side effects and amenorrhoea. When the LNG-20 intrauterine system was compared with Norplant-2, the LNG-20 users were significantly more likely to experience oligo-amenorrhoea, but significantly less likely to experience prolonged bleeding and spotting. Conclusions The effectiveness of the LNG-20 intrauterine system was similar to or better than other contraceptive methods with which it was compared. Amenorrhoea was the main reason for the discontinuation of the LNG-20 intrauterine system, usually unnecessarily, since this end-organ suppression of bleeding is benign, associated with normal oestrogen levels. Women choosing this method should be informed of potential amenorrhoea when having pre-contraceptive counselling and that absent bleeding may be viewed as a positive outcome. [source] The eigenvalues of isolated bridges with transverse restraints at the end abutmentsEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2010Nicos Makris Abstract This paper examines the eigenvalues of multi-span seismically isolated bridges in which the transverse displacement of the deck at the end abutments is restricted. With this constraint the deck is fully isolated along the longitudinal direction, whereas along the transverse direction the deck is a simple-supported beam at the end abutments which enjoys concentrated restoring forces from the isolation bearings at the center piers. For moderate long bridges, the first natural period of the bridge is the first longitudinal period, while the first transverse period is the second period, given that the flexural rigidity of the deck along the transverse direction shortens the isolation period offered by the bearings in that direction. This paper shows that for isolated bridges longer than a certain critical length, the first transverse period becomes longer than the first longitudinal period despite the presence of the flexural rigidity of the deck. This critical length depends on whether the bridge is isolated on elastomeric bearings or on spherical sliding bearings. This result is also predicted with established commercially available numerical codes only when several additional nodes are added along the beam elements which are modeling the deck in-between the bridge piers. On the other hand, this result cannot be captured with the limiting idealization of a beam on continuous distributed springs (beam on Wrinkler foundation),a finding that has practical significance in design and system identification studies. Finally, the paper shows that the normalized transverse eigenperiods of any finite-span deck are self-similar solutions that can be represented by a single master curve and are independent of the longitudinal isolation period or on whether the deck is supported on elastomeric or spherical sliding bearings. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sex-specific familial risks of urinary bladder cancer and associated neoplasms in SwedenINTERNATIONAL JOURNAL OF CANCER, Issue 9 2009Justo Lorenzo Bermejo Abstract Male gender and a family history of cancer are established risk factors for urinary bladder neoplasms. This study used the latest update of the Swedish Family-Cancer Database, which includes 42,255 bladder cancer patients, to investigate the sex-specific incidences and types of tumors in relatives of bladder cancer patients. Men with parents or siblings affected by lung cancer did not show an increased risk of bladder neoplasms. Among women, the familial association was restricted to daughters of women with lung cancer. Brothers showed higher risks than the sons of bladder cancer patients. Men older than 54 years were at an increased risk of bladder cancer only if their fathers or siblings were diagnosed after age 65 years. The present data indicated a limited contribution of smoking to the familial clustering of bladder cancer with other neoplasms. The dependence of the relative risks on the type of familial relationship probably reflected a heterogeneous character of familial aggregation. Age-specific results suggested differential risk factors for tumors diagnosed before 50 years of age versus neoplasms detected later in life. The present data may guide the design of forthcoming gene identification studies and the interpretation of the genome-wide association studies that are about to be published. © 2008 Wiley-Liss, Inc. [source] Delimiting perceptual cues used for the ethnic labeling of African American and European American voicesJOURNAL OF SOCIOLINGUISTICS, Issue 1 2004Erik R. Thomas A review of speech identification studies examining the abilities of listeners to distinguish African American and European American voices shows that Americans can recognize many African American voices with a high degree of accuracy even in the absence of stereotypical morphosyntactic and lexical features. Experiments to determine what cues listeners use to distinguish ethnicity have not yielded such consistent results, perhaps suggesting that listeners may access a wide variety of cues if necessary. An experiment involving African Americans with features of a European American vernacular demonstrated that African Americans with atypical features are difficult for listeners to identify. Analysis suggested that vowel quality and intonation could have misled respondents but did not rule out timing and voice quality as factors in identification. [source] Analytical strategies for identifying drug metabolitesMASS SPECTROMETRY REVIEWS, Issue 3 2007Chandra Prakash Abstract With the dramatic increase in the number of new chemical entities (NCEs) arising from combinatorial chemistry and modern high-throughput bioassays, novel bioanalytical techniques are required for the rapid determination of the metabolic stability and metabolites of these NCEs. Knowledge of the metabolic site(s) of the NCEs in early drug discovery is essential for selecting compounds with favorable pharmacokinetic credentials and aiding medicinal chemists in modifying metabolic "soft spots". In development, elucidation of biotransformation pathways of a drug candidate by identifying its circulatory and excretory metabolites is vitally important to understand its physiological effects. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have played an invaluable role in the structural characterization and quantification of drug metabolites. Indeed, liquid chromatography (LC) coupled with atmospheric pressure ionization (API) MS has now become the most powerful tool for the rapid detection, structure elucidation, and quantification of drug-derived material within various biological fluids. Often, however, MS alone is insufficient to identify the exact position of oxidation, to differentiate isomers, or to provide the precise structure of unusual and/or unstable metabolites. In addition, an excess of endogenous material in biological samples often suppress the ionization of drug-related material complicating metabolite identification by MS. In these cases, multiple analytical and wet chemistry techniques, such as LC-NMR, enzymatic hydrolysis, chemical derivatization, and hydrogen/deuterium-exchange (H/D-exchange) combined with MS are used to characterize the novel and isomeric metabolites of drug candidates. This review describes sample preparation and introduction strategies to minimize ion suppression by biological matrices for metabolite identification studies, the application of various LC-tandem MS (LC-MS/MS) techniques for the rapid quantification and identification of drug metabolites, and future trends in this field. © 2007 Wiley Periodicals, Inc., Mass Spec Rev [source] PERMANENT GENETIC RESOURCES: Microsatellite markers for the threatened Bliss Rapids snail (Taylorconcha serpenticola) and cross-amplification in its congener, T. insperataMOLECULAR ECOLOGY RESOURCES, Issue 2 2008H. -P. Abstract We developed and tested microsatellite markers to investigate population structure of a threatened North American freshwater gastropod, Taylorconcha serpenticola. Of the 21 primer pairs that were evaluated, 11 were readily optimized and scored, providing amplification of 12 loci that were screened for 820 specimens from 29 populations. The number of alleles across 11 of these polymorphic loci ranged from three to 20 and the observed heterozygosity varied from 0.0061 to 0.7561. All loci yielded suitable amplification products in the second species of Taylorconcha (T. insperata) and three proved to be diagnostic for these congeners, demonstrating that these markers are also useful for species identification studies. [source] Comparison of triple quadrupole, hybrid linear ion trap triple quadrupole, time-of-flight and LTQ-Orbitrap mass spectrometers in drug discovery phase metabolite screening and identification in vitro , amitriptyline and verapamil as model compoundsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2010Timo Rousu Liquid chromatography in combination with mass spectrometry (LC/MS) is a superior analytical technique for metabolite profiling and identification studies performed in drug discovery and development laboratories. In the early phase of drug discovery the analytical approach should be both time- and cost-effective, thus providing as much data as possible with only one visit to the laboratory, without the need for further experiments. Recent developments in mass spectrometers have created a situation where many different mass spectrometers are available for the task, each with their specific strengths and drawbacks. We compared the metabolite screening properties of four main types of mass spectrometers used in analytical laboratories, considering both the ability to detect the metabolites and provide structural information, as well as the issues related to time consumption in laboratory and thereafter in data processing. Human liver microsomal incubations with amitriptyline and verapamil were used as test samples, and early-phase ,one lab visit only' approaches were used with all instruments. In total, 28 amitriptyline and 69 verapamil metabolites were found and tentatively identified. Time-of-flight mass spectrometry (TOFMS) was the only approach detecting all of them, shown to be the most suitable instrument for elucidating as comprehensive metabolite profile as possible leading also to lowest overall time consumption together with the LTQ-Orbitrap approach. The latter however suffered from lower detection sensitivity and false negatives, and due to slow data acquisition rate required slower chromatography. Approaches with triple quadrupole mass spectrometry (QqQ) and hybrid linear ion trap triple quadrupole mass spectrometry (Q-Trap) provided the highest amount of fragment ion data for structural elucidation, but, in addition to being unable to produce very high-important accurate mass data, they suffered from many false negatives, and especially with the QqQ, from very high overall time consumption. Copyright © 2010 John Wiley & Sons, Ltd. [source] ,All-in-One' analysis for metabolite identification using liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry with collision energy switchingRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2005Mark Wrona The removal of bottlenecks in discovery stage metabolite identification studies is an ongoing challenge for the pharmaceutical industry. We describe the use of an ,All-in-One' approach to metabolite characterization that leverages the fast scanning and high mass accuracy of hybrid quadrupole time-of-flight mass spectrometry (QqToFMS) instruments. Full-scan MS and MS/MS data is acquired using collision energy switching without the preselection, either manually or in a data-dependent manner, of precursor ions. The acquisition of ,clean' MS/MS data is assisted by the use of ultrahigh-performance chromatography. Data acquired using this method can then be mined post-acquisition in a number of ways. These include using narrow window extracted ion chromatograms (nwXICs) for expected biotransformations, XICs for the product ions of the parent compound and/or expected modification of these product ions, and neutral loss chromatograms. This approach has the potential to be truly comprehensive for the determination of in vitro biotransformations in a drug discovery environment. Copyright © 2005 John Wiley & Sons, Ltd. 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